Electrochemical oxidation of propene using a membrane reactor with solid electrolyte

An electrochemical reactor, using ceria-based solid electrolyte coated with yttria-stabilized zirconia (YSZ), and gold and silver as the anode and cathode, respectively, has been employed for the selective oxidation of propene at 450 degrees C. On applying a direct current to this system, acrylaldehyde was formed at the gold anode, and its formation rate increased with increasing direct current. Selectivities to acrylaldehyde, CO and CO(2), based on converted propene, were 13.4, 25.6 and 61%, respectively, when the YSZ\SDC was used as an electrolyte membrane. It is found that selectivity to acrylaldehyde in this study was higher than that (SCHO=8.5%) obtained by using SDC alone as an solid electrolyte. This result suggests that YSZ coating on the ceria-based solid electrolyte leads to inhibit complete oxidation of propene at the surface of cerium oxide. From the dependence of the selectivity to oxidation products on the thickness of YSZ, it is considered that the selective oxidation of propene occurred at the Au-YSZ-gas triple phase boundary by the oxygen species pumped electrochemically through the ceria-based solid electrolyte and the YSZ.